Identification of Rab3A GTPase as an acrosome-associated small GTP- binding protein in rat sperm

Hiroshi Iida, Yuko Yoshinaga, Shigeyasu Tanaka, Kiyotaka Toshimori, Takayuki Mori

研究成果: Contribution to journalArticle査読

74 被引用数 (Scopus)

抄録

The acrosome reaction is a membrane fusion event that is prerequisite for sperm penetration through the zona pellucida. To elucidate the molecular mechanisms involved in membrane fusion, the expression and localization of Rab proteins, a subfamily of small GTPases that have been shown to play key roles in regulation of intracellular membrane traffic and exocytosis, were examined in rat testis and sperm. Reverse transcription polymerase chain reaction, immunoblot analysis, and immunofluorescence microscopy revealed that Rab3A protein, which is thought to be involved in regulation of exocytosis in neurons and endocrine cells, is associated with the sperm acrosome. The protein was undetectable in acrosome-free heads prepared by sucrose density gradient centrifugation. Immunogold electron microscopy performed on ultrathin cryosections provided further evidence that Rab3A protein is associated with the acrosomal membrane. Acrosome reaction assays revealed that synthetic peptide of the Rab3 effector domain inhibited acrosomal exocytosis triggered by calcium ionophore A23187 in a concentration-dependent fashion, suggesting that Rab3A acts as an inhibitory regulator in the acrosome reaction. In view of the putative role of Rab3A protein in membrane fusion systems, these results suggest that Rab3A could be involved in regulating the mammalian acrosome reaction by controlling the membrane fusion system in sperm.

本文言語英語
ページ(範囲)144-155
ページ数12
ジャーナルDevelopmental Biology
211
1
DOI
出版ステータス出版済み - 7 1 1999

All Science Journal Classification (ASJC) codes

  • 分子生物学
  • 発生生物学
  • 細胞生物学

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